Internal combustion engines of the reciprocating piston type are inherently sequential devices in that they typically comprise a plurality of cylinders and associated combustion chambers each of which has associated with it a number of electrically driven engine function transducers such as fuel injectors. Gasoline engines may have other sequential engine function transducers such as spark igniters and, for more technologically sophisticated engines, electrically driven intake and exhaust valve actuators which replace conventional cam shafts. The control system for such devices typically comprises an ECU having within it a plurality of high current power switches equal in number to the number of cylinders in the engine. High current capacity conductors run between the switches in the ECU and the transducers which are typically mounted on the engine itself. Because the ECU with its associated power switches is mounted some distance from the engine and further because the transducers are disposed at different locations around the engine at different distances from the ECU, the wires which connect the ECU switches to the transducers are of differing lengths.
The presence of these multiple high current conductors in itself presents a number of disadvantages including the cost and weight of the conductive material and the increase in the complexity of electrical systems found under the hood of modern automobiles. In addition, each high current conductor constitutes a source of electromagnetic interference (EMI) which, if inadvertent functions or malfunctions of other onboard devices are to be avoided, requires shielding and/or careful routing of the conductors as well as thoughtful locations of other EMI sensitive components.
In addition, the differing lengths of the conductors pose other problems including variations in current conductance caused by the delivery of electrical impulses along conductive lines of differing lengths. This is particularly problematical in the case of diesel engines where the fuel injecting transducers (injection solenoids) must be precisely controlled as to timing so that the fuel load is introduced into the combustion chamber in the correct relationship to piston position under different operating conditions. Timing the actuation of intake and exhaust valves in camless engines poses similar issues of timing precision.